With allegations of cheap practice flying like left hooks around the Olympic boxing tournament, it took an Englishman and an Irishman to settle their legitimate sporting argument with admirable cordiality, Luke Campbell getting the better of John Joe Nevin to win Great Britain's 28th gold medal of the Games.

The new bantamweight king of the Olympics, whose impish features disguise an iron will, became the team's second gold medallist after Nicola Adams made history in the women's inaugural tournament. With possibly two more golds to come, Robert McCracken's excellent squad are poised to become the best British boxing team of modern times, better even than the heroes of Melbourne, 1956, when Terry Spinks and Dick McTaggart each won gold.

Campbell, who sealed the deed 14-11 with a snap knockdown in the third round, held the loser's hand aloft to the universal acclaim of the gathering. There were tears in the blue corner, resignation in the red. "I feel great," Nevin said. "You always want more but Luke is a brilliant boxer and the best man won on the day."

We ought not get carried away with the notion that Campbell and Nevin are about to spend their holidays together. The sentiment that neither man could lose in this gloves-across-the-sea showdown owed much to noble but sentimental malarkey, however genuine was their embrace at the end. No, there was a requisite lack of warmth for as long as it lasted.

The mutual respect between Campbell and Nevin has substantial roots. They not only acknowledge the other's boxing achievements and skill but they have relatives who know one another back in Ireland. John Joe comes from a proud travelling family; Luke's grandad was Irish and ended up in England in unusual circumstances, on the lam to the UK after losing a prearranged fight to one of his fiance's brothers.

Campbell, 24, said he all but gave up boxing three years ago, after 11 months out with injury and upheaval in the coaching squad. "It was a very low point for me, 2009. I had my best 2008 and then the system changed, then it was a misery year for me. At one point I was looking to get out, didn't want to box any more. That was the environment I was in. I didn't like it. Then Rob McCracken came in, changed the system, it was enjoyable to train. I felt very confident under their wing. I went to the worst place possible in my career: what else could I be afraid of? Since Rob took over, I had 23 unbeaten fights in a row and got myself here today."

The buzz in the British camp is euphoric – despite the best efforts of the Russian sports minister, who claimed earlier in the day that Great Britain were winning undue favours in the ring. That limp accusation followed American allegations that the judges were up to no good all round.

Away from the microphones and notepads there is nothing but a flood of good humour and optimism in the team, and few boxers in the tournament have delivered on their plan better than Campbell did on Saturday night over three compelling rounds.

Fred Evans and Anthony Joshua reach for gold on Sunday and Campbell said: "We'll all be there to cheer them on. The lads are very proud. It's a very close team. We train together, we live together, we travel the world together. Each and every one of us wants the others to succeed. Fred and Joshua have got very good chances."

Nevin gave it everything but could not unlock the puzzle of the Yorkshire strategist, who revealed: "He's a very clever fighter and the plan was to draw him because if he'd have got on his back foot, that's what suits him best. I needed to take that away from him."

They had met twice, for a win apiece, and there was never going to be much in it. Campbell hides his nerves; Nevin can't – and they boxed to the rhythm of their personalities. Nevin's aggressive, hard hitting gave the impression of early dominance but the price was the long, countering rights he took from the cool Campbell, who edged the first round 5-3. It might have gone either way.

In the pros, Nevin would have been on top, perhaps, but amateur scoring is so different (a point lost on NBC's Teddy Atlas before the US network went home in a huff), more speed-chess with gloves, and Campbell kept his lead, 9-8 after two rounds, with long, raking southpaw lefts as the Irishman planted his feet to score with heavier shots.

Half way through the third, Nevin was on the seat of his pants and took a count after a blurring exchange in centre ring. Campbell was growing more audacious with his punches, determined to leave a mark his opponent would remember. The closing stanza was a dangerous dance, Nevin wanting to lead, Campbell wanting to go home. He did. With the prize.

So close and so far, forever married, the Irish and the British (more often just English), have a rivalry that is as strong as any in sport. Less than an hour before Saturday night's bout, Mo Farah secured his adopted home a 27th gold to hold on to third in the medals table, and the familiar roar filled the ExCeL Arena. And in this seething, darkened bearpit, the night belonged to Campbell and Nevin, not the objectors and whingers off stage, with their agendas and their microphones.

"Most of my family are here tonight," Campbell said, "my brothers, sister, mam and dad, my nanna, my littleboy, my partner, Leo and Lindsey, and her family too. We're going over to Ireland for a bit after all this."